The phrase "he’s an Uncle Tom" has become common, especially in African-American culture, to describe a person who is selling out to white culture and white values, perhaps even a person who is willing to betray his own people in order to remain in good standing with white "bosses." The phrase can certainly be traced to Uncle Tom’s Cabin and its popularity leading up to the Civil War and post-Civil War.
Ironically, the phrase seems to have little basis in the actual character Uncle Tom. He does not betray his people, nor does he try to ingratiate himself with his white "masters." Instead, he stands true to his Christian principles. This means that he refuses to be dishonest or untrustworthy, but that includes a refusal to betray Cassy’s whereabouts to Simon Legree, despite the fact that it means that Legree will murder Tom instead. In other words, the actual character is willing to die rather than to betray one of his own people, yet the term became synonymous with a sellout. How did that happen? It’s hard to say.
Uncle Tom’s Cabin was so widely read and so influential in creating anti-slavery sentiment that many people criticized it as unrealistic. As a result, Harriet Beecher Stowe wrote another book defending her portrayal of slavery and the South as thoroughly realistic. The book, A Key to Uncle Tom, is a hodgepodge of anecdotes, quotations, and philosophical musings/arguments.
Many times, Stowe quotes unnamed people to substantiate various parts of the story. For example, an unnamed Presbyterian minister swears that he himself saw a young girl escape across the Ohio River on broken ice the way Eliza did. This evidence might not pass the acid/James-Frey test of today. Nevertheless, we decided it could be a great source for information relating to the character analyses and have indicated when we used it, but if you’re dying to read it for yourself, you can find it here.